Several devices and methods are known for the landing of space probes on celestial objects.
In the case of lunar missions, the moon landing of a lunar carrier module of a lunar vehicle is accomplished with retrorockets, for example, with the lunar module being able to lift off again.
In the case of missions to planets with atmospheres, parachutes are used, for example, to slow down the probes, with the probes being carried by a support module equipped with braking balloons to soften the impact on the ground.
It is found that the set of probes produced up to now comprise a carrier structure and a payload, with the latter, for example, being a travel module of the “rover” type docked in the carrier structure.
The carrier structure is able to absorb the shock of landing and is located below the payload after landing.
If the payload is a module that can move such as a travel module, this load has to descend from the carrier structure after landing to become operational.
An unloading system, ramps, crane, or other type, accordingly has to be provided, with this system increasing the weight of the whole unit.
When the probe lands with the help of balloons or parachutes, the payload has to pass through a zone where there are remainders of the descent system such as linkages or of the deflated fabric, and there is a risk that the wheels of the payload will become entangled in these remainders.
In such a case, inclined sections can be provided to cover the area where the deflated balloons are, for example in particular in the ExoMars project of the ESA.
To mitigate these problems, the probe called the “Mars Scientific Laboratory” of NASA is slated to use a different concept based on a carrier structure that includes a braking parachute device that then releases a transport module that will then perform a quasi-stationary propelled flight above the Martian ground, to lower a Martian module to the ground by means of a crane and a cable.
Such a stationary flight is a complex and costly solution in the matter of propellants, while on the other hand this solution avoids encumbering the module landing site with remainders of the descent system and permits the module to be placed in a well-defined zone.